<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2015, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package    CodeIgniter
 * @author    EllisLab Dev Team
 * @copyright    Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
 * @copyright    Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
 * @license    http://opensource.org/licenses/MIT    MIT License
 * @link    http://codeigniter.com
 * @since    Version 3.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * PDO Oracle Forge Class
 *
 * @category    Database
 * @author        EllisLab Dev Team
 * @link        http://codeigniter.com/user_guide/database/
 */
class CI_DB_pdo_oci_forge extends CI_DB_pdo_forge {

    /**
     * CREATE DATABASE statement
     *
     * @var    string
     */
    protected $_create_database    = FALSE;

    /**
     * DROP DATABASE statement
     *
     * @var    string
     */
    protected $_drop_database    = FALSE;

    /**
     * CREATE TABLE IF statement
     *
     * @var    string
     */
    protected $_create_table_if    = 'CREATE TABLE IF NOT EXISTS';

    /**
     * UNSIGNED support
     *
     * @var    bool|array
     */
    protected $_unsigned        = FALSE;

    // --------------------------------------------------------------------

    /**
     * ALTER TABLE
     *
     * @param    string    $alter_type    ALTER type
     * @param    string    $table        Table name
     * @param    mixed    $field        Column definition
     * @return    string|string[]
     */
    protected function _alter_table($alter_type, $table, $field)
    {
        if ($alter_type === 'DROP')
        {
            return parent::_alter_table($alter_type, $table, $field);
        }
        elseif ($alter_type === 'CHANGE')
        {
            $alter_type = 'MODIFY';
        }

        $sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
        $sqls = array();
        for ($i = 0, $c = count($field); $i < $c; $i++)
        {
            if ($field[$i]['_literal'] !== FALSE)
            {
                $field[$i] = "\n\t".$field[$i]['_literal'];
            }
            else
            {
                $field[$i]['_literal'] = "\n\t".$this->_process_column($field[$i]);

                if ( ! empty($field[$i]['comment']))
                {
                    $sqls[] = 'COMMENT ON COLUMN '
                        .$this->db->escape_identifiers($table).'.'.$this->db->escape_identifiers($field[$i]['name'])
                        .' IS '.$field[$i]['comment'];
                }

                if ($alter_type === 'MODIFY' && ! empty($field[$i]['new_name']))
                {
                    $sqls[] = $sql.' RENAME COLUMN '.$this->db->escape_identifiers($field[$i]['name'])
                        .' '.$this->db->escape_identifiers($field[$i]['new_name']);
                }
            }
        }

        $sql .= ' '.$alter_type.' ';
        $sql .= (count($field) === 1)
                ? $field[0]
                : '('.implode(',', $field).')';

        // RENAME COLUMN must be executed after MODIFY
        array_unshift($sqls, $sql);
        return $sql;
    }

    // --------------------------------------------------------------------

    /**
     * Field attribute AUTO_INCREMENT
     *
     * @param    array    &$attributes
     * @param    array    &$field
     * @return    void
     */
    protected function _attr_auto_increment(&$attributes, &$field)
    {
        // Not supported - sequences and triggers must be used instead
    }

}
